As a female terminal in the related art, a female terminal described in Patent literature 1 is known. FIG. 4(A) is a perspective view of a female terminal described in Patent literature 1, and FIG. 4(B) is a longitudinal sectional view cut along an axial direction of the female terminal of FIG. 4(A). FIG. 5 is an exploded perspective view of the female terminal of FIG. 4(A).
In FIG. 4(A), a female terminal 100 is made of a female terminal main body 110, a cap 120, and a spring contact 130. Both the female terminal main body 110 and the spring contact 130 are formed by punching a metal plate, and the female terminal main body 110 is formed to be rounded in a cylindrical shape by press working. The cap 120 is formed by a synthetic resin by injection molding.
Hereinafter, the female terminal main body 110, the cap 120, and the spring contact 130 will be simply described.
As illustrated in FIG. 4(B), in the female terminal main body 110, a cap locking part 110A, a spring accommodation part 110B, a spring stopper 110C, a convex part 110D, and a fastening part 110K are formed in order from a tip end side (male terminal insertion side: left side of the drawing).
In addition, the cap locking part 110A is formed at the furthest tip end of the female terminal main body 110, and an inner diameter of the cap locking part 110A is set to be slightly larger than the maximum outer diameter of the spring contact 130. An outer circumferential part which protrudes outward in a radial direction of the cap locking part 110A is formed as a locking projection which is meshed with a locking claw which is formed inside the cap 120.
An inner diameter of the spring accommodation part 110B is formed to be substantially equivalent to the maximum outer diameter of the spring contact 130, and the spring contact 130 is accommodated in the spring accommodation part 110B. The spring accommodation part 110B is formed to be rounded in a cylindrical shape by press working. Therefore, as illustrated in FIGS. 5 and 6, at a joint 110T (refer to FIGS. 5 and 6) at which one end surface and the other end surface oppose each other in a circumferential direction of the spring accommodation part 110B, generation of a slight void is unavoidable.
An inner diameter of the spring stopper 110C is formed to be smaller than an outer diameter of a linking part 130R of the spring contact 130. Therefore, as the linking part 130R abuts against the spring stopper 110C, the spring contact 130 accommodated in the spring accommodation part 110B is restricted not to be moved further rearward (in a direction of the fastening part 110K), and the spring contact 130 is prevented from falling out from a rear side of the female terminal main body 110.
The convex part 110D is formed in a circumferential direction of a trunk part of the female terminal main body 110, and an outer diameter of the convex part 110D becomes substantially equivalent to an outer diameter of the cap 120. Accordingly, as an inner diameter of a terminal accommodation chamber of a connector housing in which the female terminal 100 is accommodated becomes substantially equivalent to the outer diameter of the cap 120, when the female terminal 100 is accommodated in the terminal accommodation chamber of the connector housing, the convex part 110D of the female terminal main body 110 is pressurized to an inner circumferential surface of the terminal accommodation chamber, and inclination or rattling of the female terminal 100 is prevented.
The fastening part 110K is formed in a U shape when viewed from a front surface before connecting the female terminal 100 and an electric wire which is not illustrated to each other, and when connecting the female terminal and the electric wire, by placing a core wire of the electric wire in a U-shaped bottom part, and by fastening both U-shaped end parts to each other on the inside using a tool, the electric wire is compressed to the fastening part 110K. Accordingly, the electric wire and the female terminal main body 110 are electrically connected to each other.
As illustrated in FIG. 4(B), the cap 120 is formed mainly by integrating an inlet 120G, a stopper wall 120S, and an outer wall 120W by a synthetic resin.
The stopper wall 120S is linked to the inlet 120G, and has a cylindrical shape having an inner diameter which is equivalent to the inlet 120G and an outer diameter which is substantially equivalent to the inner diameter of the cap locking part 110A of the female terminal main body 110. When the cap 120 is attached to a tip end of the female terminal main body 110, the cap 120 is pressed to the cap locking part 110A of the female terminal main body 110, and at this time, on the stopper wall 120S, an end surface thereof abuts against the linking part 130R of the spring contact 130 in the spring accommodation part 110B, and the spring contact 130 is restricted not to be moved forward.
The outer wall 120W is integrally formed at an interval having a width which is the same as a thickness of the cap locking part 110A, on the outer side of the stopper wall 120S. At a lower end on an inner circumferential surface of the outer wall 120W, the locking claw which is meshed with the locking projection of the female terminal main body 110 protrudes.
In the spring contact 130, the metal plate is punched to be a perforated plate, in which both end parts of multiple long plate spring pieces 130L in which a center part is curved to the inner side (center side when being rounded in a cylindrical shape) in an arc shape, are respectively linked to each other by linking parts 130R and 130R, and is used to be rounded in a cylindrical shape.
Next, an assembling method of the female terminal 100 will be described.
First, both ends of the long plate spring piece 130L come into contact with each other so that both ends of both linking parts 130R and 130R of the spring contact 130 are linked to each other, and maintaining this state, without contracting the spring contact 130 in a diameter direction, the spring contact 130 is inserted into the spring accommodation part 110B of the female terminal main body 110. At this time, as illustrated in FIG. 6(B), the joint 110T at which one end surface and the other end surface in the circumferential direction of the spring accommodation part 110B oppose each other, and a joint part where one end surface and the other end surface in the circumferential direction of the long plate spring piece 130L in the spring contact 130 oppose each other, are disposed to overlap each other in the radial direction. This is because performance as a point of contact deteriorates since the contact cannot be sufficiently ensured when the long plate spring piece 130L is disposed at the joint 110T of the spring accommodation part 110B.
After this, while pressing the stopper wall 120S of the cap 120 to the cap locking part 110A of the female terminal main body 110, the cap 120 is attached to the tip end of the female terminal main body 110.
At this time, an end surface of the stopper wall 120S which is pressed to the cap locking part 110A of the female terminal main body 110 abuts against the linking part 130R of the spring contact 130, and the spring contact 130 is held in the spring accommodation part 110B.
In addition, at the same time, the locking claw of the outer wall 120W is meshed with the locking projection on the outer circumference of the cap locking part 110A, and the cap 120 and the female terminal main body 110 are reliably integrated with each other.
Next, a problem of the female terminal 100 will be described by using FIG. 6.
FIG. 6(A) is a side view of the female terminal of FIG. 4(A), and FIG. 6(B) is a sectional view cut along arrow A-A in FIG. 6(A). In FIG. 6(B), at the joint 110T of the spring accommodation part 110B, there is a case where a void is generated between end surfaces in which one end surface and the other end surface oppose each other in the circumferential direction of the spring accommodation part 110B, or a case where a step is generated between the end surfaces in a case where the inner diameters of one end surface and the other end surface of the spring accommodation part 110B are different from each other. When the joint 110T and the long plate spring piece 130L overlap each other, since the contact between the joint 110T and the long plate spring piece 130L cannot be sufficiently ensured, the performance as a point of contact of the joint 110T deteriorates. Therefore, the long plate spring piece 130L which is at a position which overlaps the joint 110T is not considered as a point of contact.
Here, the long plate spring piece 130L is not disposed at the joint 110T, and work for disposing a void part T of the spring contact 130 is performed.
However, the spring contact 130 which is accommodated in the spring accommodation part 110B of the female terminal main body 110 is restricted not to be moved in an insertion direction of the terminal by the spring stopper 110C provided in the female terminal main body 110, and is restricted not to be moved in a disengaging direction of the terminal by the cap 120, but a structure in which the movement in a rotating direction is restricted is not provided.
Therefore, when any rotating force is applied to the spring contact 130, for example, the spring contact 130 rotates in an arrow direction R of FIG. 6(B), and as illustrated in FIGS. 6(B) to 6(C), a case where the void part T of the spring contact 130 is disengaged from the upper part of the joint 110T, and the regular long plate spring piece 130L is disposed on the joint 110T, can be generated.
However, since the performance of the long plate spring piece 130L on the joint 110T as a point of contact cannot be ensured, one spring becomes useless, and a case where all of the springs cannot be used as a point of contact is generated.